The present disclosure relates to Global Navigation Satellite System (GNSS) navigation, and more particularly to a method and apparatus for detecting poor Doppler measurement results in GNSS navigation.
With the development of electronic technologies, the GNSS receiver module has become a standard feature in some electronic products such as mobile phones, tablet computers, cameras and wearable products. Existing GNSS receivers provide the position, velocity, and time (PVT) for navigation. The accuracy of the velocity (speed and direction) is highly dependent on the accuracy of Doppler measurement results.
In an urban environment, for example, multipath (MP) signal interference can be very severe, which affects the quality of Doppler measurements. In instances when the receiver is moving, a Doppler shift of a MP signal is different from a Doppler shift of a line of sight (LOS) signal. The Doppler shift of the MP signal due to the movement of the receiver can be opposite to the Doppler shift of the LOS signal, in some cases. In this case, if the LOS signal is shielded, or otherwise blocked, and the MP signal is received, the opposite Doppler measurement result will lead to an incorrect velocity and direction, and further lead to a potentially large error during navigation. Therefore, it is desirable to screen out poor Doppler measurement results before PVT calculation.
The background description provided above is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.